Unite and Momentum are set to back rival candidates for the battle to become Lewisham East’s next Labour MP, the Guardian has learned.

The development is the latest in an interesting dynamic on the Labour left, first dragged into the open by the battle to become Labour’s next general secretary. Momentum founder Jon Lansman pitched himself against Jennie Formby from Unite, who was backed by the leaders’ office. Lansman eventually withdrew from the race and Formby was selected.

The Guardian understands Momentum’s national co-ordinating group is likely to back Lewisham councillor Sakina Sheikh, a former student campaigner who has close links with the grassroots group. Unite have already formally backed Islington councillor Claudia Webbe, a member of Labour’s national executive committee and a former advisor to Ken Livingstone.

Both candidates have been interviewed by Momentum chiefs to try to win the group’s backing. A Momentum source suggested they wanted to back a candidate with local credentials. “The local Momentum heavily backs Sakina and it feels like she will get the national backing, as they are keen to make sure it’s a local candidate with the endorsement of local members,” the source said.

Unite announced on Tuesday it was backing Webbe, the more experienced candidate, calling her “a lifelong socialist who tirelessly fights the corner of working people, and for justice for those let down by our political system.”

Unite Politics (@UnitePolitics)

Unite is proud to be supporting @ClaudiaWebbe to become Labour’s next MP for #LewishamEast. A lifelong socialist who tirelessly fights the corner of working people, and for justice for those let down by our political system. She will be a huge asset in Parliament. https://t.co/0PtAmOSnTU

Two other candidates have also been shortlisted, councillor Brenda Dacres, who stood unsuccessfully to be Lewisham mayor earlier this year, and Janet Daby, Lewisham’s deputy mayor.

Lewisham East’s local party is controlled by party centrists, who are likely to organise for Daby or Dacres other candidates. A Momentum source said the seat could be “a real tough battle” for the left in the local party.

Just had excellent meeting with Disability Policy Team at No10 Downing St to propose ways to make air + train travel more accessible + less of a nightmare for disabled passengers. Pleased it's being taken seriously.

Gaza: Nakba day protests as Palestinians bury those killed in embassy unrest – live updates

A pro-remain campaign group has been fined £2,000 by the official elections watchdog for failing to declare donations totalling £30,000 in the EU referendum, the Press Association reports. The Electoral Commission said Best for Our Future Ltd failed to include a £20,000 donation from the GMB trade union and a further £10,000 from Unison in its spending return. The two unions were each fined £500 for not accurately reporting donations while Unison received a further penalty of £1,000 for late payment of an invoice.

Electoral Commission chief tells MPs it needs to be able to impose larger fines

The Commons culture committee has just started taking evidence from the Electoral Commission as part of its “fake news” inquiry.

The witnesses are: Claire Bassett, chief executive of the Electoral Commission; Bob Posner, its director of political finance and regulation and legal counsel; and Louise Edwards, its head of regulations.

Bassett starts by saying the commission thinks electoral law is old and fragmented. But she would not go as far as to say it is not fit for purpose, she says.

She says the commission has made a whole series of recommendations for reforms. Some of them it has been pushing for for 15 years, she says.

She says the rules about the regulation of campaign spending need to be updated.

And she says the commission needs tougher powers. It can only impose a fine of £20,000. That is too low, she says. It has been described as the cost of doing business.

Electoral Commission chief says it needs to be able to impose larger fines.

And she says the commission needs tougher enforcement powers, for example in relation to being able to require third parties to disclose information.

We’ve got some new Guardian/ICM polling out today. And its good news (ish) for Boris Johnson and Jacob Rees-Mogg

Customs union

First, we asked about the customs union. As the psephologist John Curtice explained in a recent blog for What UK Thinks, the existing polling on this topic is not very satisfactory. If you ask people if they are in favour of customs checks for people and goods coming from the EU, they tend to say yes. But if you ask people if they are in favour of staying in the customs union (which would remove the need for said checks), they also say yes. “One feature of the polling and survey evidence to date is that few pollsters and researchers have dared attempt to ask voters specifically about what customs arrangement the UK should have with the EU,” Curtice says.

Well, we had a go. We asked people which of these three statements on customs after Brexit they most agreed with. The results were:

It is very important to leave the customs union properly, so the UK can strike its own trade deals: 35%

It is very important to stay in the customs union, so firms can trade with the EU more easily: 24%

The best solution might involve some sort of compromise, perhaps along the lines of the customs partnership, because the alternative proposals are both flawed: 26%

We did not put names to the three options, but ‘leaving the customs union properly’ is the position associated with Tories like Boris Johnson, the foreign secretary, or Jacob Rees-Mogg, head of the 60-strong European Research Group. Staying in the customs union is the Labour party position. And a compromise seems to be what Theresa May wants. She argues that the customs partnership, supposedly her favoured option, does involve leaving the customs union properly, but Brexiters don’t accept that, which is why we mentioned it in this context.

The post-Brexit customs policy championed by Brexiters like Boris Johnson is most popular with voters, the poll suggests. A third of voters want a customs policy that prioritises leaving the customs union properly, while only a quarter of voters want to stay in a customs union, while another quarter favour a compromise. But you could also read the figures as showing that 50% of voters are opposed to a clean break with the customs union. Some 15% of respondents said they did not know.

Extending the transition

The post-Brexit transition period is due to come to an end in December 2020 but there has been a lot of speculation that it will have to be extended. Damian Green, the former first secretary of state, became the latest person to float this idea at the weekend. Downing Street insists this will not happen, although there have been some hints that they could shift.

We told respondents there was talk of the transition being extended to allow new customs arrangements to be introduced and asked them if they would support or oppose this. Here are the results.

Nearly half of voters oppose extending the Brexit transition, the poll suggests. Some 43% of people said they were against this idea, even when it was suggested this might be necessary to allow time for new customs arrangements to be introduced. But 38% of people said they were in favour. Another 19% said they did not know.

As ICM’s Alex Turk points out, opinion was polarised along political party and leave/remain lines.

While views are fairly evenly split, more of the British public oppose (43%) than support (38%) extending the Brexit transition period beyond 2020. These views are polarised along party and EU referendum lines: two-thirds (67%) of 2016 Leave voters and 3 in 5 (62%) of those intending to vote Conservative oppose extending the transition period, whereas three in five (59%) 2016 Remain voters and almost half (49%) of those intending to vote Labour support extending the transition period.

Voting intention

The Conservatives retain a 3-point lead over Labour, the poll suggests. This is unchanged from the 3-point the Tories had in the Guardian/ICM poll two weeks ago.

ICM Unlimited interviewed a representative online sample of 2,050 adults aged 18+, between 11 and 13 May 2018. Interviews were conducted across the country and the results have been weighted to the profile of all adults. ICM is a member of the British Polling Council and abides by its rules.

Unemployment at 4.2%, lowest rate since 1975

The number of people in work has reached a new record, while earnings have grown in line with inflation, new figures show, the Press Association reports. Employment increased by 197,000 in the quarter to March to 32.3m, the highest figure since records began in 1971, giving a record rate of 75.6%. Unemployment fell by 46,000 to 1.42m, giving a jobless rate of 4.2%, the lowest since 1975, according to the Office for National Statistics (ONS). Average earnings increased by 2.6% in the year to March, down by 0.2% on the previous month, but 0.2% up on a year ago. The latest CPI inflation figure is 2.5%.

Senior ONS statistician Matt Hughes said:

With employment up again in the three months to March, the rate has hit a new record, with unemployment remaining at its lowest rate since 1975.

The growth in employment is still being driven by UK nationals, with a slight drop over the past year in the number of foreign workers. It’s important to remember, though, that this isn’t a measure of migration.

Growth in total pay remains in line with inflation, meaning real earnings are flat on the year.

My colleague Graeme Wearden has more on the business live blog.

UK real wages rise, as German economy slows - business live

May accused of subverting devolution as MSPs prepare to refuse consent to EU withdrawal bill

Theresa May’s Brexit difficulties show no signs of easing. She is chairing yet another meeting of the cabinet’s key Brexit sub committee this afternoon to discuss customs with, as my colleague Jessica Elgot reports, the Conservative MP Jacob Rees-Mogg indicating that the Tories who want a harder form of Brexit have no intention of backing down.

Pessimism about Brexit customs impasse after Rees-Mogg remarks

Read more

And Scotland is also implacable. Today the Scottish parliament is set to vote for a motion refusing to grant legislative consent to the EU withdrawal bill. This is itself will not block the legislation - even though the Scotland Act 2016 says the UK government should not “normally” legislate on devolved matters without the consent of the Scottish parliament, the supreme court in the article 50 case said this was not legally enforceable - but it will show that the goodwill underpinning the devolution settlement is being eroded.

Speaking about the issue on the Today programme this morning Mike Russell, the Scottish government’s Brexit minister, said:

Devolution is the settled constitutional will not just of the Scottish people, of the whole of the UK. Westminster is trying to subvert that and to change that by the back door.

The parliament will vote to reject legislative consent for the withdrawal bill - not just the Scottish National party in government, I think all the parties save the Conservatives will actually vote for that.

More on that later, in what promises to be a busy day. Here is the agenda.

11.30am:Boris Johnson, the foreign secretary, takes questions in the Commons.

1pm: May chairs a meeting of the cabinet’s key Brexit sub committee to discuss customs.

After 1pm: MPs debate the data protection bill. The government will seek to overturn last night’s Lords vote calling for a new Leveson-style inquiry into the press.

After 2pm: MSPs in Edinburgh begin a debate on a motion to refuse legislative consent to the EU Withdrawal bill. They are due to vote at 5pm.

3.45pm:Sajid Javid, the new home secretary, gives evidence to the Commons home affairs committee about the Windrush migrants.

5.30pm: May holds a press conference with the Turkish president, Recep Tayyip Erdogan, after talks in Downing Street.

As usual, I will be covering breaking political news as it happens, as well as bringing you the best reaction, comment and analysis from the web. I plan to post a summary at lunchtime and another in the afternoon.

I try to monitor the comments BTL but normally I find it impossible to read them all. If you have a direct question, do include “Andrew” in it somewhere and I’m more likely to find it. I do try to answer direct questions, although sometimes I miss them or don’t have time.

If you want to attract my attention quickly, it is probably better to use Twitter.